The present invention is in the field of treatment of leafy vegetables or other fresh commodities in general. Specifically the invention is in the field of treating leafy vegetables to enhance their product shelf life, reduce microbial loading, and improve product appearance and quality.
Leafy vegetables or other fresh commodities are typically treated with aqueous solutions of sodium hypochlorite, also known as bleach. This treatment is conducted to enhance the product shelf life and maintain product quality. Because of the desirability of reducing the amount of chlorine introduced into the environment, it would be desirable to have an alternative treatment to enhance product appearance and shelf life in leafy vegetables or other fresh commodities.
The instant claimed invention is a method to extend the shelf-life, reduce the microbial load, and enhance product appearance and quality in leafy vegetables comprising applying directly to the leafy vegetable or other fresh commodities of the like a stabilized aqueous alkali or alkaline earth metal hypobromite solution.
The following terms have the indicated meanings:
xe2x80x9cAPCxe2x80x9d refers to aerobic plate count bacteria
xe2x80x9cCFUxe2x80x9d refers to colony forming units.
xe2x80x9cYMxe2x80x9d refers to yeast and mold count
The instant claimed invention is a method to extend the shelf-life, reduce the microbial load, and enhance product appearance and quality in leafy vegetables comprising applying directly to the leafy vegetable or other fresh commodities of the like a stabilized aqueous alkali or alkaline earth metal hypobromite solution.
Stabilized aqueous alkali or alkaline earth metal hypobromite solutions are commercially available under the trademark STA-BR-EX(copyright) from Nalco Chemical Company, One Nalco Center, Naperville, Ill. 60563, (630) 305-1000. These solutions of stabilized aqueous alkali or alkaline earth metal hypobromite typically contain from about 1 to about 30 percent by weight alkali or alkaline earth metal hypobromite. Preferably these solutions contain from about 4 to about 15 percent by weight alkali or alkaline earth metal hypobromite.
The pH of the stabilized aqueous alkali or alkaline earth metal hypobromite solution is from about 8 to about 14, preferably from about 11 to about 14.
Leafy vegetables are selected from the group consisting of leaf lettuce, head lettuce, spinach, cauliflower, broccoli, celery, cabbage, or the like. The preferred leafy vegetable is leaf lettuce.
The method of applying a stabilized aqueous alkali or alkaline earth metal hypobromite solution to the leafy vegetable or any other commodity of interest is conducted by applying the solution directly to the leafy vegetable. There are many methods of applying solutions to leafy vegetables that are known to people of ordinary skill in the art of leafy vegetables or any other commodity of interest. The preferred way of doing this is to fully immerse the entire leafy vegetable into a solution of stabilized aqueous alkali or alkaline earth metal hypobromite. The application time, also known as the immersion time, is from about 5 seconds to about 7 minutes, preferably from about 5 seconds to about 5 minutes, and most preferably from about 5 seconds to about 3 and a half minutes and most highly preferably about 3 minutes.
The solutions of stabilized aqueous alkali or alkaline earth metal hypobromite applied directly to said leafy vegetables in an amount of from about 0.05 to about 5,000 ppm total available halogen as chlorine, preferably from about 2 to about 200 ppm total available halogen as chlorine.
Leafy vegetables treated with solutions of stabilized aqueous alkali or alkaline earth metal hypobromite have a shelf life and appearance similar to those leafy vegetables treated with bleach (sodium hypochlorite). Therefore, the application of stabilized aqueous alkali or alkaline earth metal hypobromite to leafy vegetables is a viable alternative treatment to the standard treatment of leafy vegetables with a chlorine based material.